Initially unaware of the potential timing, I coincidentally happened to be at a sports bar in a small town in the Midwest when Michael Sam was picked up in the NFL draft by his college home state St. Louis Rams in May.

The crowd of drinkers and diners watching live sports network coverage on monitors ringing the room were cognizant yet nonplussed about the historic announcement of the NFL’s first “out” gay player. Even Sam’s passionate and exuberant celebratory-cake-smeared ESPN-televised kiss with boyfriend Vito Cammisano was relegated to a communally blasé reaction.

America, it seems, is more accepting of gay professional athletes than some might have anticipated – or still think.

Surprisingly, though, few gay professional athletes have acknowledged their sexual orientation. Those in “major” sporting leagues, especially among men and until recent notable exceptions, have remained in the closet while still active competitors.

Sports are proving to be the final frontier for gay acceptance.

A decade ago, most considered it improbable that entrenched attitudes about military service and civil marriage, as well as employment equality and cultural acceptance, would allow advancement in those arenas prior to the advent of acknowledgment by gay athletes. Nor would many have expected that broad and strong support for all would become the dominant societal standard so soon.

Yet progress in sports has proven more elusive. In fact, in a national survey of LGBT Americans conducted last year by the Pew Research Center, only four percent considered professional sports leagues friendly to gays, while 59 percent saw them as unfriendly. Only two percent mentioned athletes as important figures in advancing gay rights on a national level.

While a small number of athletes in a variety of endeavors have revealed their sexual orientation, the high-profile major-money-making sports have, until recently, remained devoid of “out” athletes.

Following the conclusion of the 2012-13 NBA season, 12-year pro basketball player Jason Collins came out in a column he penned for Sports Illustrated, subsequently becoming a free agent. In February, after signing with the Brooklyn Nets, Collins became the first publicly gay athlete playing in any of the “Big Four” pro sports leagues of baseball, basketball, football or hockey. At the time, NBA Commissioner Adam Silver indicated in interviews that it was “disappointing it took this long for this moment to finally happen in the sports world.”

Silver went on to say that “this is an area where no one in sports should be too proud.” “I’m cautious about celebrating it too much because where sports has led in so many ways, this is one of the places where we’ve trailed. This should have happened long ago,” he added.

Silver noted that he “looks forward to the day when it’s no longer news for a team to sign an openly gay player” while understanding why Collins’ signing was “such a big deal.” “It is a big deal for this league, and hopefully, in the way that sports can uniquely impact society, that this is an area where, for the next Michael Sam, they feel that much more comfortable coming out.”

When Sam came out in February, delaying a public announcement until finishing his college career, sports observers anticipated that several prominent professional football players would reveal that they are gay. That has yet to occur.

Only last week did Arizona State University’s Chip Sarafin become the first active Division I college football player to come out publicly, in an interview published in Compete magazine. Sarafin’s announcement closely followed Division I basketball player Derrick Gordon’s likewise groundbreaking revelation at U-Mass.

Despite the hesitation of gay athletes to come out, every high school, college, amateur and professional athlete that does so swings the closet door open a bit wider for others to follow. The now commonplace support of teammates, coaches, institutions and, importantly, fans has also oiled the hinges.